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" j w. T. PQwEpL AUTOMATIC TELEPHONE SYSTEM original File Nov. a, I'1915 z smug-.snep 2 one hundred terminals.

Patented Nov. 11, 1924.l

UNITED STATES PATENT OFFICE.

WINFREI) T. POWELL, `O F CHICAGO, ILLINOIS, ASSIGNOR T0I AUTOMATIC ELECTRIC i COMPANY, 0F CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS. i

AUTOMATIC TELEPHONEl SYSTEM.

Application filled November 8, 1915, Serial No. 60,271'. Renewed December 19, 1921. SerialNo. 523,583.

To all Lo/1,0m t may concern.'

Be it known that I, IVINFRED T. Pownm., a citizen of thekUnited States ot America, and a resident 'of Chicago, Cook County, Illinois, have invented `certain new and useful Improvements in Automatic Telephone Systems, oi" which the following is a speci fication.

This invention relates to impnovements in automatic telephone systems and more particularly to improvements in the automatic switches used in such systems.

In automatic telephone systems where the impulse sending device(y is capable of transmitting ten successive impulses at the'most, it is customary to provide numerical switching mechanism capable of responding to not more than ten successive impulsesby providing a shaft with ten notches carrying wipers adapted to engage one of ten bank levels, each level being provided withr ten terminals.

is limited to connect with any one of one invention `to' provide anv automatic switch capable of selecting more than the customary By this arrangement it is thus possibleto increase the capacity ott an exchange without increasing the number of switches. n Y

A further object ot this invention is the provision ot an automatic selecting switch which is very positive and efficient in its operation.

To the foregoing and other useful ends this invention consists'ot matters herein-` after set 'forth and claimed.'

The features ot this invent-ion will be more clearly understood by reference' to the accompanying drawings, inwhich Fig. A1 represents a diagrammatic illustration of the switching yfeatures, whereby one of two sets ot shaft wipers may be used.

Figs. 2 and `3k taken together represent ay complete connection in an automatic telen vphone system embodying the principles of this invention. i

In Fig.' 4 are shown the essential parts ot a connector switch similar to that shown in Fig. tito which my inventionhas also been applied.

It is obvious that-in such a sys tem each selecting or connecting mechanism impulse-sending y responding to the respective digits of the i called number. This impulse-sendingniechanisin may be similar to that shown in United States Letters Patent tio J.l G. Bless-- ing No. 1,119,394 granted Dec. 1, 1914.

The subscribers individual switch C (Fig. 2)` is kot the general typeot subscribers switch shown 'in British patent to T. G.

'MartinNo v1419 of `1910, being, however ot the particular type disclosed in United States Letters Patent to F.`Newfortli, J r. No. 13,901 reissued Apr. 13, 1915.

The master switch Dis of the same general type as that disclosed in British patent to B. WV. James No. 26,301r iof 1906, being however of the particular type disclosed in British patent to T. Cr. Martinr No. 1419 ot 1910, referred to previously. The function ot the master switch, as-is well known, is

\ to maintain the plungers of all the idle individual switches in position to engage the terminals of an idle trunk line.

The selector switch E (Fig. 2) is of the general type-of selector switch disclosed in United States Letters Patent No.` 815,321 granted March'13, 1906 to Keith, Erickson vand Erickson, except that the side switch is dispensed with and the circuits are modified to adapt them to y operate in a` system in which the central office apparatus is controlled by impulses delivered over the two sides ot the line in series, as shown in British Vpatent to T. Cr. Martin No. 10,376 of 1912,

and is further modiiied to operate in accordance with the principles of my invention.

Among other details the selectorE comprises a bank of contacts arranged in horizontal rows or levels, which contacts are adapted to be engagedby two sets'oic wipers 10, 11, 12 and 13, 14, 15 carried upon a shaft (not shown) which 'has a vertical and rotary movement controlled by the vertical and rotarymagnets 16 and 17. The operation of the switch is controlled through the medium .ofV the line relay 18 which in turn controls the vertical and rotary magnets. When rotated onto the bank terminals, all of the wipers engage co-rresponding contacts. However, one set of wipers is connected with the extending circuits while the other set is disconnected therefrom. The switching from one set of wipers to the other is controlled by therelayl 19, which relay, when innormal position, permits the line conductors and release trunk conductor to be connectedto the wipers .10, 11 and 12.

lWhen said yrelay 19 .is energizedtlie said conductors are then connected to the wipers 13, 14 and 15. The energizing circuit of relay 19 is adapted tobe close-dby the switch shaft carrying the arm'20, which arm closes the no-rmal springs 21 .while the switch shaft is being raised for-the lastor tenth step. Thel relay 19 will lock, upon energizing, and switch the extending circuits to the other set ofwipers. At the same time that relay 19 is operated the switch shaft is restored to its normal position, so that the switch in to release ltheir armatures after their. energizing circuits are broken-a locking relay A 25 .and a switching relay 26. The control.-

ling circuits and operation of the magnets will be more clearly set forth when the operation of the switch is described.

The connector switch H (Fig. 3) is of the same general type of connector switch disclosed vin United States LettersfPatent No. 815,176 granted "March 13, 1906 to Keith, Erickson and Erickson, the circuits, however, beingmodified to adapt the switch to operate ina system in which the central oflice apparatus is controlled by impulses delivered over the two sidesof the line in series, as shown in British patent to T. Gr. Martin, No. 1419 of 1910. Among other details the connector comprises a bank of contacts arranged in horizontal levels, which contacts are adapted to bevengaged by a set of wipers 27, 28, and 29 carried upon a shaft r(not shown) which has a vertical and rotary movement controlled vby the vertical and rotary magnets 30 and 31. The olifferent operations of the switch are controlled through the medium of the line relay 32. The usual back bridge relay 33 is provided through which the called subscriber is supplied with current for talking purposes. The release relay 34 and private control relay 35 are slow acting. The magnet 36 is the usual release magnet, while 37 is the busy relay and 38 is the ring cutoff relay. The private magnet 39 controls the usual side switch wipers 40, 41, 42 and 43. rlhe relay 44 is adapted to supply ringing cui rent from the generator R to the called line forl signalling purposes. The connector switch shaft (not shown) carries the arm 45, which when said shaft leaves its lowest or normal position, permits the pairs of off-normal springs 46 and 47 to close contact. Busy signalling Vcurrent is furnished in theusualmanner from the busy signalling machine Q. -f l The line switch J and allvthe subscribers station K are similar in all respects to the line switch C and subscribers station A.

A general description of the apparatus involved having been given, it will now be explained how a connection can be established between the line of a calling substation A and a called substation J.

Since the apparatus hereindisclosed is in general well known in the art, and is described in the publications herein referred to, its operation will be explained in a more or less general manner.

When the subscriber at substation A removes his receiver preparatory to making a call, an energizing circuit is closed for the line relay 48 of the line switch C. The re lay 48 upon energizing closes a circuit for the pull -in winding 49 which operates to thrust the plunger (not shown) on the end of the plunger arm 50 into a vbank of contacts, thereby forcing springs 51, 52, 53 and 54 into engagement with springs 55, 56, 57 and 58, thereby extending the connection to the selector E. The cut-off arm 59 is also operated to remove the line relay 48 from control of the calling substation. The relay 48 being slow acting maintains the circuit of pull-in winding 49 for a. short time after its own circuit is broken. When the connection is thus extended to the selector E, an energizing circuit is established for the line relay 18 of said selector which extends from ground Gsthrough the lower winding of line relay 18, springs 60 and 61, springs 58 and 54, line conducto-r 62, to and through substation A, return line conductor 63, springs 51 and 55, springs 64 and 65 and the upper winding of the relay 18 to the battery B. The relay 18, upon energizing, closes a circuit from ground Gr4 through springs 66 and 67' and the relay 23 to the battery B. The relay 23, upon energizing, closes a circuit from ground G5 through springs 68, 69 and 70, along release trunk conductor 71 through springs 56 and 52 to a point 72, thence over two paths, one of which extends fit) through the hold-iii winding 73 of line switch C to the battery B, the other path eX- tends along conductor 74 to the connector private bank contacts associated `with the calling line. This ground potential protects the substation A against seizure as long as the receiver is removed from the switclihoolr. Due .to the fact that relay 48 is slow actingit maintains the circuit of winding 49 until the holding ground from G5 is supplied over the release conductor 71 to the holding winding 73 of line switch C to maintain the plunger in its operated position.

Assuming the called number to be 220, the calling subscriber now operates his impulsesender or calling device for the first digit 2, thereby causing the impulse springs 8 to be separated. twice momentarily, each time breaking the circuit of line relay 18 of the selector E. The slow acting relay 23 does not deenergize during the momentary interruptions of its circuit by the relay 18 and therefore each time that relay 18 deenergizes an impulse is transmitted over av circuit extending from ground G4, through springs 66 yand 75, springs 7 6, springs 77 and 78, relay 24 andthe vertical magnet 16 to the battery B. The vertical magnet receives two impulses over this circuit and operates to raise the switch shaft and wipers twosteps to a position opposite the second level of bank contacts, and at the same time the shaft controlled contact springs 7 9 and are closed. The slow acting relay 24 energizes when the first impulse of current is transmitted` through it and maintains its armature in an attracted position during the` remaining impulses of the digit.' In its energized position said relay 24 closes a cir-y cuit from ground G5 through springs 68 and 69, springs 81 and 82 and relay 25 to the battery The relay 25, upon energizing, closes a circuit for itself, independent of springs 81 and 82 of relay 24 which extends from ground G5 through springs 68, 69and 70, release conductor 71, springs 83, springs 84 and the relay 25 to the `battery l5. .lhen the relay 24 deenergizes after the last impulse is deliveredto the vertical magnet, the relay 25 remains energized, and the circuit ofthe rotary magnet 17 is closed over a` circuit that extends from ground G5 through springs 68 and 69, springs 81 and 85, springs 86 and the rotary magnet 17 to the battery B. The rotary magnet, upon energizing, rotates the shaft wipers one step and by opening the springs 83, disconnects ground G5 from relay 25 tothereby deenergize said relay, and by separating springs 87 opens the circuit of relay 26 which was short-circuited over a circuit which extends from ground G? through springs 68, 69 and 7 0., release conductor 71, springs 83, springs 84,'springs 79, springs 87, relay 26, conducgizing at this time.

tor 92, release conductor 71, springs 70, 69 and 68 back to ground G5. As long as relay 25 is energized the switching relay 26 is thus short-circuited. When the rotary magnet movesfthe shaft wipers the lirst step it unlocks relay, 25 and opens the circuit of the switching relay 26 to prevent it from ener- The relay 25, upon de energizing, opens the circuit of the rotary magnet at springs 86. The rotary magnet 17, upon deenergizing, permits the pairs of springs 83 and 87 to closecontact.k If the first trunk of the second level is idle, the

switching relay 26 will immediately ener-v gize and extend the connection through to the switch ahead. If, however, this trunk is busy, the private wiper 12 finds the contact with which it engages provided with a guarding ground potential, which is transmitted to the relay 25 over a circuit that eX-` tends from ground upon said guarded contact through private wiper 12, springs 88 and 89, springs 90 and 91, springs 87, springs 79 and the relay 25 to the battery B. The relay 25 energizes to close a locking circuit for itself as previously traced as well as to close the circuit of the rotary magnet. The rotary magnet will therefore again en ergize to rotate the shaft wipers onto the contacts of the second trunk line. second `trunk line is also busy the private wiper 12 will find the contact with whch it en gages also provided with a guardingground potential. A circuit will again be closed `to the relay 25, as before, which will close theV ,rotary magnet circuit to :advance the wipers another step and again open the circuit of relay 25. The rotary magnet continues to advance the wipers step-by-step over the contacts until the non-grounded contact of an idle line is `reached by the wiper 12. 1When an idle line has been located and the rotary magnet permits the springs under its control to engage a circuit is closed that extends from ground G5, through springs 68, 69 and 70, release con ductor 71, conductor 92, switching relay 26, springs 87, springs 7 9, relay 25 to the battery li. Relay 25 does not receive suilicient current ovei` the last circuit to cperatively energize because of the comparatively high resistance of relay 26. Relay 26, upon energizing, opens the contact of springs 76 and separates springs 90, 64 and 61 from springs 91, 65 and 60 and forces them into so i contact with springs 93, 94 and'95 respecsprings 56 and 52 and the holding'winding 73 of line switch C to the battery B. Another branch extends from the'point 72 of the last circuit to the private normal conductor 74 and thence to the private bank contacts of the calling line. This circuit maintains the relay 26 and the winding 73 ener- I' gized, after their original energizing circuits arebroken by the relay 23, which deenergizes shortly after the line relay 18 is 'disconnected from the line.

The calling subscriber now operates the calling device for the next digit 2, where.

upon the impulse springs Sare separated twice momentarily, each time breaking the circuit of the line relay 32 of the connector H. The relay 34 ofthe connector being slow acting does not deenergize during the momentary interruptions of its circuit by Vthev relay 32, and consequently each time that the latter relay deenergizes, an impulse is transmitted over a circuitl extending from ground G7 through springs 115 and '116, springs 117 and 113, relay 35, vertical magnet side-switch wiper 42 (in rst position) to the battery, B. The vertical Vmagnet receives two impulses over this circuit -and operates to raise the switch shaft andwipers two steps to a position opposite the second level of bank contacts and at the same time the shaft controlled springs 46 and 47 are closed.

The relay is energized by the first impulse transmitted through it and being slow acting maintains its armature attracted dur-` ing the succeeding. impulses of the digit.

In its energized position said relay 35 closes a circuit from groiuid G8 through springs 119 and 12() andthe' private magnet 39 to the battery B'. This circuit is broken whenl the relay 35 deenergizes a short time after the last impulse has been delivered to the vertical magnet. The breaking of this circuit causes the private magnet 39 to deenergize thus permitting the side switch to pass to secondposition. In reaching second position the side switch wiper 42! connects the battery to the rotary magnet-,31; said battery having previously been connected tothe vertical magnet 30. The subscriber now e operates the calling device for the last digit O, in Aresponse to which the'connector line relay 32 operates to transmit ten impulses to the rotary magnet 31, whereby the shaft -wipers are rotated onto the contacts of the desired line. The circuit of the'rotary magy net extends from ground G" through springs 115 andA 116, springs 117 and118, relay 3,5,

springs 121, rotary magnet 31, side-switch wiper 42 (in second position) to the battery B. The relay 35 operate-s in response to this digit in the same manner as for the previous digit to cause the private magnet 39 to advance the side switch another step, i. e., from second yto third position. By the engagement of the side switch wipers and 41 with their third position contact points the connection is completed with the called line. Upon the engagement of the side-switch wiper 43 with its third position contact point, a circuit is completed through the cutofi' winding of the line switch J. This circuit extends from ground G9 through the side switch wiper 43 (in third position), private wiper 28, bank contact 122 and the cutov winding 123 to the battery B. The cut-off winding, upon energizing, operates to disconnect the line relay 124 from the called line. The connection of ground G9 with the connector private bank contact 122 and its multiples, prevents the called line from being seized by some other connector switch. switch wiper 42 with its third position contact point the circuit of the ringing relay 44 is closed which extends from ground G10 through the interrupter 125, ringing relay 44, springs 126 and the side-switch wiper 42 (in third position) to the battery B. The ringing relay 44 is energized intermittently, due to the interrupter 125, and operates to disconnect the called line from the- -calling line and to bridge the ringing current generator R across the called line to signal the called subscriber. Upon the remo-val of the receiver, the called substation will be provided with talking current through the windings of the back bridge relay 33, which upon energizing, closes a circuit from ground G9 thro-ugh the side switch wiper 43 (in third position) springs 127 and the relay 38 toV the battery B. The relay 38 upon energizing, opens the circuit or the ringing relay at springs 126 and closes a locking circuit for itself through springs 12S independent of the springs 127. The calling subscriber is provided with talking current through the windings of the line rel lay 32. The connections are now in talking condition and the subscribersmay converse; talking current traveling over the heavy conductors.

Upon the completion of the conversation the calling subscriber, by returning his receiver to the switch hook, ropens the circuit of the connector l line relay 32. The relay 32, upon deenergizing, opens the circuit of relay 34, which in turn, upon deenergizing, removes the holding ground from the release trunk conductor 114, and in addition closes a circuit from ground G7 through springs and 116, springs 117 and 129, olf normal springs 46 and the release magnet 36 to the lil() lll) battery l. The release magnet upon energizing, operates to remove the retaining `Vhen fthe holding ground is removed from the release conducto-r 1111,k the energizing circuits of the switching relay 26 of selector E and of winding' 7 3 are opened. The deenergization of relay 26 completes a circuit from ground GL through springs 66 and 75, springs 76, springs 77 and 130,. off normal springs 80 and release magnet 22 tothe battery B. The release magnet, upon energizing, removes the retaining double-dog to permit the shaft to restore to normal position, the circuit of the release'magnet being opened when the shaft reaches its lowest position. The deenergization of the winding 7 3 of line switch C releases the plunger arm and cut-off arm 59, thus permitting the line switch C to be returned to normal.

The selector E is capable of responding to two digits or series of impulses from the calling device provided (in this instance) that the first digit called be 0. Suppose that the selector E is seized for a` call as previously yexplained and that the number desired is 0220. The calling subscriber then operates his calling device for the first digit `0 thereby transmitting ten impulses over the line, which ten impulses would operate to raise the switch shaft, (larrying the arm 20, ten steps to close the Contact of springs 21, while the last impulse is being delivered. A circuit would then be closed from ground Gf* through springs 66 and 75', springs 76, springs 77 and 78, springs 21, to spring 96, thence over two paths one of which extends through spring 97 and the release magnet 22 to the battery B, the other path extends through spring 96 and the relay 19 to the battery B. The release magnet 22, upon energizing, restores the switch shaft to normal position. The relay 19, upon energizing, forces spring 99 into contact with spring 98 and separates springs 96 and 97 from spring 98 thereby closing a locking circuit for itself extending from ground G5 through springs 68, 69 and 70, springs 99 andf98 andthe said relay 19 to the battery B. A further result of the energization of relay19 is the shifting of springs 100, 101 and 89 from their back contacts 102, 103 and 88 into engagement with their front contacts 104, 105 and 106 respectively,whereby the wipers 10., 11 and 12 are disconnected from the extending circuits and the wipers 13, 141 and 15 substituted in their stead. One contact in each bank level is shown in Fig. 1, in which X is the lower bank of line contacts, Y is the upper bank of line contacts, while Z contains two sets of private contacts, the upper one, such as 107, is used in conjunction with line contacts 108 and 109 when a connection is extended to a group of connectors such as H, while the lower contact 110 is used ywith line contacts 111 and 112 when a connection is extended to a different group of connectors such as H. It may be stated that the connectors H and l-l are similar in all` respects, but that `they serve to complete connection with different lines.

The calling subscriber will operatehis calling device for the second digit, which may be any digit from 1 tog0, in this instance it was taken to be 2, kwhereby two impulses would be transmitted over the line to again operate the selector E to raise its switch shaft and wipers twor steps to a poVH sition opposite the second level of bank contacts after .which the wipers are automatically rotated onto an idle set of con; tacts in said second level to extend the connection over wipers 13, 111 and 15 to an idle connector, such as H. The operations of the apparatus from this point are similar to those hereinbefore described and it isnot thought necessary to illustrate or describe the same.

It is to be understood that the location and adjustment of the springs 21 of the selector E can be such that the arm 20 will come in contact with said springs when the shaft wipers are opposite any level of bank contacts. F or instance, if the shaft closes said springs when the wipers are opposite the eighthlevel, the capacity of the switch instead of being 19 levels would be 17 levels, and soon.

It is thus seen that this invention contemplates a very efiicient form of selector switch which has two movements in the vertical plane with the usual horizontal movement of selecting trunks. The switch shaft having the usual ten notches and being provided with two sets of wipers, one set being adapted forl use when one series of digits is employed while the other set is brought into use for another series of digits. In this manner the capacity of an exchange may be increased without increasing the number of numerical trunk selecting switches. vIt is obvious to those versed in the art that this invention is directly applicable to connector switches of any well known type, and as shown in Fig. 1, `may be added thereto with a very little change in the circuits of the connector. In' Fig. 4 only the essential parts of the connector have been illustrated and like parts are numbered the same as in Fig. 3. The relay 19ZL corresponds to the relay 19 of selector E, Fig. 2. The operating'l magnets and other p-arts it will be understood are the samel as those of the connector in Fig. 3.

While the illustration and description of this invention has been confined toI automatic switches ofthe well known type that have first, ,ak vertical movement to select` groups and a rotary movement to find a line in the selected group, it will, of course, be understood, that this invention is capab-le of use in connection with other forms of automatic switches in which different characters of movement are employed for selecting groups and lines.

What I claim asmy invention is:

1.*In a telephone system, a line, a pair of movable contact makers for said line, aplurality of stationary contactsyassociated with each maker, means for advancing said makers adjacent to one of their respective associated contacts and for then releasing said makers from said advanced position and for switching said line into engagement with one of said make-rs, as a result of said first movement of the switch, and for then operating the said last makers to extend the linev therefrom.

2. In a telephone system, a line, a pair of movable contact makers for said line, a plurality of stationary contacts associated with each maker, means `for bodily Vadvancing said makers adjacent to one of their respective associated contacts and for then releasing said makers from said advanced position and for switching said line into engagement with one of said makers, as a result of said first movement of the switch, and for then operating the said last makers to extend the line therefrom. y

3. In a telephone system, a line, a pairof movable contact makers for said line, said line normally connected to one of said makers, a plurality of stationary contacts associated with each maker, means for advancing said makers adjacent to one of their respective associated contacts and for then releasing said makers frein said advanced `position and for switching said line into engagement with the other of said makers, as a result of said first movement of the switch, and for then operating the said last makers to extend therline therefrom.

4,. In a telephone system, a line, a pair of movable contact makers for said line, a plurality of groups of stationary co-ntacts associated with each maker, means for advancing said `makers adjacent to one of their respective associated groups of contacts and for then releasing said makers from said advancedposition and for switching said line into engagement with one of said makers, as a result of said first movement of the switch, and for then operating the said last makers to extend the line therefrom.

5. In a telephone system, a line, a pair of movable contact makers for said line, said line normally connected to one of said makers, a plurality of groups of stationary contacts associated with each maker, means for advancing said makers adjacent to one of their respective associated groups of contacts and for then releasing said makers from said advanced position and for switching said line into engagement with the other of said makers, as a result of said first movement of the switch, and for then operating the said last makers to extend the line therefrom.

6. In a telephone system, a line, a pair of movable contact makers for said line, a plurality of stationary contacts associated with each maker, means involving an impulse sender and a magnet responsive thereto, for advancing said makers adjacent to one of their respective associated contacts, means involving a release magnet for then releasing said makers from said advanced position, and means involving a switching relay for switching said line into engagement with one of said makers, as a result of said first movement of the switch, and for then operating the said last makers to extend the line therefrom.

7. In a telephone system, a line, a pair of movable contact makers for said line, a plurality of stationary contacts associated with each maker, a shaft for carrying said makers, means for advancing said shaft whereby the makers may be advanced adjacent to one of their respective associated contacts and for then releasing the shaft for removing the makers from their advanced position and for switching said line into engagement with one of said makers, as a result of said first movement of the switch, and for then operating the said last makers to extend the line therefrom.

8. In a telephone system, a line, a pair of movable contact makers for said line, a plurality of stationary contacts associated with yeach maker, a. shaft for carrying said makers, means for advancing said shaft whereby the makers may be bodily advanced adjacent to one of their respective associated contacts and for then releasing the shaft for removing the makers from their advanced position and for switching said line into engagement with one of said makers, as a result of Asaid first movement of the switch, and for then operating the said last makers to extend the line therefrom.

9. In a telephone system, a line, a pair of movable contact makers for said line, said line normally connected to one of said makers, a plurality of stationary contacts associated with each maker, a shaft for carrying said makers, means for advancing said shaft whereby the makers may be advanced adjacent to one of their respective CII y ment of the switch, and tor then operatin y associated contacts and for then releasing the shaft for removing the makers from their advanced position and for switching said line into engagement with the other 'of said makers, as a result or' said iirstmovement of the switch, and l'or then operating the said last makers to extend the line therefrom.

10. ln a telephone system, a line, a pair of movahle contact makers iior said line, a plurality of groups ot stationary contacts associated with each maker, a shaft for carrying said makers, means for advancing said shaft whereby the makers may he advanced adjacent to one ot their respective associated groups of contacts and for then releasing the shaft ior removing the makers from their advanced position and for switching said line into engagement with one of said makers, as a result of said first movement of the switch, and for then operating the said last makers to extend the line therefrom.

11. In a telephone system, a line, a pair of movable contact makers for said line, said line normally connected to one ot' said makers, a plurality oitl groups o stationary contacts associated with each maker, a shaft liorcarrying said makers, means for advancing said shalt whereby the makers may be adxf'anced adjacent to one of their respective associated groups of contacts auditor 4then releasing the shaft tor removing the makers :trom their advanced position and for` switching said line into engagement with the other out1 said makers, as a result or' said first movet) the said last makers to extend the line theretrom.

12. .ln a telephone system, a line, a pair oitmovable contact makers tor said line, a plurality ci stationary contacts associated with each maker, a shaft for carrying. said makers, means,v involving an impulse sender vand a magnet responsive thereto, tor advancing said shalt whereby the makers may he advanced adjacent to one ot their respective associated contacts, means involving a release magnet for then releasing the shaft ior removing the makers from their advanced position, one o't said pair or' movable contact makers normally connected to said line, means involving a switching' relay for switching said line into engagement with another of said u'iakers, lines terminating in said stationary contacts, busy test circuits associated with said lines, and means whereby when said iirst means is again operated tomove the makers adjacent to a group of contacts the makers may he moved into engagement with one ot said lines and it the line is busy the makers are advanced automatically through the instrumentality of the corresponding busy test circuit onto the next contact.

13. ln a telephone system, an automatic switch, a plurality ol groups ci lines associated with said switch, ay plurality of groups of wipers for engaging said lines, said switch having means ifor giving said `wipers a plurality of numerical operations .said switch having means-tor giving said wipers a plurality ot' numerical operations to select a group and a non-numerical operation for selec-ting an idle line in the selected group, means comprising a relay for switching a connection 'trom one oit said groups olf' wipers to another group.

15V. In a telephoney system,` an automatic switch, a plurality of groups of lines associated with said switch, a plurality groups ol' wipers ior engaging said. lines, said switch having means for giving said wipers a plurality of numerical operations to select a group and a non-numerical opertion for selecting an idle line in the selected group, and means for extending a connection through only one of said groups ci wipers. 1

16. ln a telephone system, an automatic switch, a plurality ot groupsot lines associated with said switch, a plurality of groups of wipers for engaging said lines, said switch having means 'for giving said wipers a plurality off numerical operations to select agroup and a non-numerical operation for selecting an yidle line iny the selected group, a relay, means controlled hy said relay for extending a connection through only one of said groups oil wipers.

17. In a telephone system, an automatic switch having an extending circuit, said switch having numerical andnon-numerical operations, a plurality of groups of lines associated with said switch, a plurality ot groups of wipers for engaging said lines, one oi said groups ot wipers being normally connected with said extending circuit -whle the` other set is disconnected therefrom, and means controlled hy the numerical operation of said switch tor disconnecting said connected group and tor connecting said disconnected group.

` 18. In a telephone system, an automatic switch having an extending circuit, `said switch having numerical `and non-numerical operations, a plurality of groups of lines associated with said switch, a plurality of groups of wipersv fon engaging said lines, one ot said groups of wipers being normally connected with said extending circuit while the other set is disconnected therefrom, and means comprising a relay controlled by the numerical operation oi' said switch for dise connecting said connected group and for connectingsaid disconnected group.

19. In a telephone system, an automatic switch, a line extending to said switch,

groups of lines extending from said switch, av plurality of groups of wipers for engaging said lines, means for transmitting a seriesvof impulses to operate said switch and to cause sa'id switch to automatically select an idle line in one of said groups of lines and means comprising a relay in said switch for electing one of said groups of wipers,

a circuit for said relay, said ycircuit adapted to be closed by thetransmission of a predetermined `number of impulses.

20. In a telephone system, -an"automatic switch, plurality of groups of lines terminating in said switch, `a plurality of groups ofwipers for said switch :tor engaging said lines, means for transmitting a plurality of series of impulses for operating said switch, and means responsive to an impulse of the first series for releasing said switch and for .electing a group of wipers.

2l. In a telephone system, an automatic switch, a plurality of groups of lines terminating insaid'switch, a plurality of groups of wipers orsaid switch for engaging said lines, means for transmitting a plurality of series of impulses foroperating said switch, means' in said switch responsive tocan impulse of the first series Vfor releasing said switch and for electing a group of wipers.

22. In a telephone system, an automatic switch, aplurality of groups of lines ter- `ries with said stepping relay, and -means comprising a test wiper cooperating with test contacts in the bank of said switch for short circuiting said switching relay and for energizing said stepping relay it the said test contacts are busy.

24. In a telephone system, a selectively movable switch having a motor magnet, a stepping relay orclosing the circuit of said magnet, a switching relay connected in series with said stepping relay, means comprising a test wiper co-operating with test contacts in the bank of said switch for short circuiting saidl switching relay and for energizing said stepping relay it the said test contacts are busy, and contacts in the energizing circuit oi" said stepping relay controlled by said magnet, whereby the stepping relay and motor magnet constitute an interrupter mechanism for moving said test wiper over busy test contacts.

25. In artelephone system, a selectively movable switch having a motor magnet, a stepping relay for closing the circuit ol' said magnet, a switching relay lconnected in series with said stepping relay, means comprising a test wiper cooperating with test contacts in the bank of said switch for short circuiting said switching-relay and for energizing said stepping relay if the said test contacts are busy, contacts in the energizing circuit of said stepping relay controlled by said magnet, whereby the stepping relay and motor magnet constitute an interrupter mechanism for moving said test wiper over busy test contacts, andA contacts operated by said switching relay when said testjwiper arrives at an idle contact for shifting the connection of said wiper to the other side of the switching relay, 26. In a telephone system, a selectively movable switch having a motor magnet, a stepping relay for closing the circuit of said magnet, a switching relay connected in serieswith said stepping relay, means comprising a test wiper cooperating with test contacts in the bank of said switch for short circuiting said switching relay and for energizing said stepping relay if the said test contacts are busy, contacts in the energizing circuit of said stepping relay controlled by said magnet, whereby the stepping relay andy motor magnet constitute an interrupter mechanism for moving said test wiper over busy test contacts, contacts operated by said switching relay when said test wiper arrives at an idle contact for shifting the connection ofsaid wiper to the other side of the switching' relay, and means for completing the circuit of said relays over a new path including said wiper, said stepping relay remaining inoperative.

27. In a telephone system, a selectively movable switch, normally open talking cir'- cuit conductors in said switch, a switching relay fory closing said conductors, a motor magnet and a stepping relay adapted to cooperate to effect selective movement of said switch, a test wiper and cooperating test contacts governing said selective movement, and suitable circuits for controlling said relays and said magnet, both of said relays being simultaneously connected to said wiper whereby when the said test contacts are busy the switching relay is prevented from energizing and the stepping relay is energized.

Q8, In a telephone system, a selectively movable switch comprising a motor magnet, a stepping relay therefor, a line switching relay, a test wiper and a banlr of test contacts, means for completing a circuit through said relays, a branch of said circuit for short circuiting said switching relay and for energizing the stepping relay, means cooperating with said stepping relay for initially closing the circuitoi said motor magnet, said magnet thereafter being under the sole control of the stepping relay, contacts insaid lfirst circuit and its branch opened by said magnet upon its energization, and alternative connections from said relays to the test wiper whereby the continued short circuiting of the switching relay` and the reenergization of the stepping relay is made dependent upon the presence of a test potential on the. test contact with which the test wiper has been moved into connection by ythe said energization of the motor magnet.

29. In a telephone system, a selectivelymovable switch having a motor magnet, means for operating said switch comprising a stepping relay for controlling said motor magnet, a line switching relay connected in` series with said' stepping relay, and means comprising a test wiper cooperating with busy test-contacts for short circuiting said switching relay and `for energizing said stepping relay.

`30. In a telephone system, alselectively i movable switch having a motor f magnet, .means for operating said switch comprising a stepping relay for controlling said motor magnet, a line switching relay connected in scrieswithsaid stepping relay, means comprising a test wiper cooperating with busy y test contacts for short circuiting said switching relay' and for energizing said stepping relay, and contacts in the energizing circuit of said stepping relay under control layk and magnet constitute an interrupter mechanism for causing step -by step movement of said test wiper. l

31. `In a telephone system, the combina-v tion with an automatic switch having directive primary movement for selecting groups and automatic secondary movement for selecting an idle line in a selected group, of

primary and secondary motor magnets in said switch, a steppingy relay controlling said secondary magnet, talking conductors, a switching relay controlling their continuity,

meansfor connecting said relays in series during the secondary movement of said switch, a test wiper, and a connection from said test wiper to the junction of said relays; 32.1In a telephone system, the combination with an automatic switchhaving directive primary movement for selecting `f groups and automatici secondary movement a switching relay controlling their cono tinuity, means cooperating with said stepping relay at the end of the primary move- `ment `of said switch for initiating the secondary movement, means for closing Ia circuit through said relays iii-series, and means y.

comprising a test wipercooperating `with busy test contacts for short circuitin Vsaid switching relay and for energizing said stepping relay.

33. In a telephone system, the combina- .80

tion in a selectively movable switch, of an operating mechanism comprising apcooperating stepping relay andmotor magnet for driving the switch, a switching relay vfor closing the line circuit, means for closing a,

circuit for said switching relay in a preliminary movement of said switch, a test wiper and cooperating'busy vand idle test contacts, and circuit, connections `tor prev venting the energization kof saidv switching` relay and for energizing saidi stepping relay while the said test` wiper engages busy test contacts, said circuitsy including connections from said wipery to both fot said relays. Y f

34. In a telephone system, an automatic switch comprising passive contacts'and a cooperating active contact, means outside said switch for rendering certain of said passive contacts busy, means for causing a preliminary movement of said switch to bring said active contact `into association with said passive contacts, a control relay and a circuittherefor closed in said preliminary movement, a` short circuit around said control relay to prevent its energization, a magnet and a cooperating stepping relay `for advancing said activecontact oversaid passive contacts, means operated each time said active contact comes into engagement with a'passive contact for opening said short circuit, and circuit connections kfor maintaining a second short circuit independent oi the irstas-long as said active contact engages busy passive contacts. y.

35. In a telephone system, a mainl geX- change and a branch exchange, an automatic switch, having motion in twointersecting planes, trunk lines leading from said switch to each exchange, means 'for operating said switchV in one plane in lresponse to the first digit only of a called number to cause said switch to select trunks to the main exchange and fory operating said switch in the same plane in response to the first and second digits of a called number to canse said switch to select a trunk to the branch exchange, said lirst digit inthe second instance ycausing said switch to advance nect through one of said wipers to atriink ,25

`change over one of ysaid wipers, and for operatinfg said switch in response to the iirst and second digits yof a called numbery to cause said switchto connect with a trunk line leading to the branch exchange over they other of said wipers. l

37,In va telephone system, a main exchangejand a branch exchange, an auto-` matic switch, trunk lines leading from said switch tol each exchange,"a pair oi. wipers `for said switch, means for operating said switch inv one instance in 'accordance to the firstmdigitonly of the called number to con- Ylead'ingto the main exchange and for operating-said switch in another instance in accordance with both the first and second digits ofthe called number to connect with a 'trunk line leading to' said branch ex-v change, said first digit in the second instan'cencjausing sai'd `switch to advance and then releasejbeforefthe second digit is called.

38., Inla telephone system, an automatic switch, trunk linesVv leading from said switch divided into main and subgroups, a pair ot wipersfor said switch for reach main group of trunk lines, means for transmitting a single seriesfvof impulses to operate said `-.switch to selectv a subgroup of one of said `tend a connection over one of said pairs oi'l maingroups over itsassociated wiper and for transmittinga plurality of series of im-A pulses to y'said `switch to cause the sainel to vselecta subgroup in anothervof said main groupsthrough another pair of wipers.

first and secoiidfvseleetor switch, a directively operable primary magnet foi-'controlling the operation ofsaid switch, a plurality of pairs of .wipers forsaid switch, means tor operating said primary-magnet in one instancejbythe,.impulses corresponding to the firstdigit only of a called number to exwipers,l and for operating said yprimary ymagnet in another instance by the impulses corresponding to the irst and second digits of tlie'called number to extend a connection over kanother of said pairs of wipers.

`4.0. In a telephone system, a plurality of exchanges, an automatic switch in one exchanvre, local trunk linesvleading from said switczhjother trunk lines leading vfrom said switch to the other exchanges, a plurality of pairs of wipers for said switch, means for operating said switch in accordance with the rst digit only' of a called number to extend a connection from said switch to one or said other trunk lines via one of said pairs of wipers and for operating said switch in accordance with the first and second digits of a called number to extend a connection from said switch to one of said local trunk lines via another pair of said wipers. y

' 4l.A in a telephone system, a first selector having groups of wipers for use in connecting a calling and called line, means in said switch for changing from one group or' said wipers to another group of said wipers and means foroperating and releasing the same, both of said means responsive to the calling of the iirst digit in the number of the called' line, means'for reoperating said switch when the secondrligitis called, the second digit being the same as the first, and means for preventing the release of said switch when it is reoperated, the said switch being therebyenabled to extendfthe connection in the direction of the called line.

42. ln a telephone system, a calling and a called line, a telephone number assigned to the called line, the rst two digits in said number being the same, a irst selector having groups of wipers operable in response to the calling of' the iirst of said digits, means for automatically releasing said irst L'selector the iirst time it is loperated and for switching from one of said groups ot wipers to another, means for preventing the release of said first selector when the second ofsaid digits is called, the said first selector being joperated to extend the con- Anection in the direction of the called line,

and other vswitches operable responsive to the remaining digits to complete the connection.

43. In a telephone system, means includ- "fing a drop back selector for connecting call- 39. In a telephone system, a combined ing and called lines, said selector having groups of wipers, groups of trunk lines accessible to said selector, calling dials at the stations on said lines, a shaft for operating `all ofthe wipers of said selector responsive to a single operation Vof the dial at a calling station to connect with an idle trunk in one of said groups of trunks, and means requiring two successive and identical operations of the dial at said calling station to operatefsaid selector to connect with an idle trunk in another of said groups.

44. In a telephone system, an automatic switch, two sets of wipers for said switch, said wiper sets being vmechanically connected so, as to always move together, a

yline incoming to said switch and normally associated with one of said wiper sets, means for connecting with said line for the purpose of operating said switch thereover,

llO

restoring means for said switch, means responsive to the operation of said switch in a movement of definite and predetermined extent for shifting said line into association with the other `of said Wiper sets, and means also responsive to such primary movement for actuating said restoring means While maintaining the connection to said line, whereby the said switch may `be reoperated.

Signed by .me at Chicago, Cook County, 10 Illinois, this 3rd day of November, 1915. `VVINFRED T. POWELL. Witnesses:

CHAS. M. CANDY, LOUIS M. LANDA. 

